Polysiloxane sunscreens

Abstract

The present invention relates to novel sunscreens on the basis of polysiloxanes, to their preparation and to their use, especially in formulations for the protection against harmful effects of sunlight.

1. Polysiloxanes comprising the following structural elements per molecule:
   one element of formula (H 3 C) 3 —Si—  (I),
 
   one element of formula —O—Si(CH 3 ) 3   (II),
 
 at least two elements selected from the groups (A), (B), (C) and (D), 
 (A) 0 to 100 elements in arbitrary order which are either identical or different from each other selected from the group consisting of formulae
   —O—Si(CH 3 )[CH(CH 3 )R 1 ]—  (IIIa),
 
   —O—Si(CH 3 )(CH 2 —CH 2 —R 1 )—  (IIIb),
 
   —O—Si(CH 3 )[C(═CH 2 )R 1 ]—  (IIIc), and
 
   —O—Si(CH 3 )(CH═CH—R 1 )—  (IIId);
 
 
 (B) 0 to 100 elements in arbitrary order which are either identical or different from each other selected from the group consisting of formulae
   —O—Si(CH 3 )[CH(CH 3 )R 2 ]—  (IVa),
 
   —O—Si(CH 3 )(CH 2 —CH 2 —R 2 )—  (IVb),
 
   —O—Si(CH 3 )[C(═CH 2 )R 2 ]—  (IVc), and
 
   —O—Si(CH 3 )(CH═CH—R 2 )—  (IVd);
 
 
 (C) 0 to 100 elements in arbitrary order which are either identical or different from each other selected from the group consisting of formulae
   —O—Si(CH 3 )[CH(CH 3 )R 3 ]—  (Va),
 
   —O—Si(CH 3 )(CH 2 —CH 2 —R 3 )—  (Vb),
 
   —O—Si(CH 3 )[C(═CH 2 )R 3 ]—  (Vc), and
 
   —O—Si(CH 3 )(CH═CH—R 3 )—  (Vd);
 
 
 (D) 0 to 100 elements in arbitrary order which are either identical or different from each other selected from the group consisting of formulae
   —O—Si(CH 3 )[CH(CH 3 )R 4 ]—  (VIa),
 
   —O—Si(CH 3 )(CH 2 —CH 2 —R 4 )—  (VIb),
 
   —O—Si(CH 3 )[C(═CH 2 )R 4 ]—  (VIc), and
 
   —O—Si(CH 3 )(CH═CH—R 4 )—  (VId);
 
 
 1-200 elements in arbitrary order of formula —O—Si(CH 3 ) 2 —(VII), 
 and optionally 1-20 elements in arbitrary order of formula —O—SiH(CH 3 )—(VIII), wherein 
 R 1  is a UV-B light absorbing group, 
 R 2  is a UV-A light absorbing group, 
 R 3  is a UV-C light absorbing group, and 
 R 4  is a broadband light absorbing group; 
 with the proviso that the molecule comprises at least two elements belonging to different groups (A), (B), (C) and (D). 
 
     
     
       2. The polysiloxanes according to  claim 1  wherein the number of elements of group (A) is 1 to 50 and the number of elements of group (B) is 1 to 50. 
     
     
       3. The polysiloxanes according to  claim 1  containing 5 to 80 elements in arbitrary order of formula —O—Si(CH 3 ) 2 —. 
     
     
       4. The polysiloxanes according to  claim 1  wherein elements of formula VIII are absent or substantially absent. 
     
     
       5. The polysiloxanes according to  claim 1  wherein R 1  is derived from a benzalmalonate and R 2  is derived from an amino substituted hydroxybenzophenone. 
     
     
       6. A light screening agent which comprises at least one polysiloxane according to  claim 1 . 
     
     
       7. The light screening agent according to  claim 6  for the protection of human skin and/or human hair. 
     
     
       8. The light screening agent according to  claim 6  for the protection of UV sensitive plastic materials and medicinal products. 
     
     
       9. Cosmetic or pharmaceutical compositions comprising at least one polysiloxane as defined in  claim 1  and at least one pharmaceutically and/or cosmetically acceptable excipient. 
     
     
       10. The cosmetic or pharmaceutical compositions according to  claim 9  which additionally further comprises at least one UV-A screening agent, UV-B screening agent and broadband screening agent. 
     
     
       11. The cosmetic or pharmaceutical compositions according to  claim 9  comprising from 0.2 wt. %-20 wt. % the polysiloxanes based on the total weight of the composition. 
     
     
       12. The cosmetic or pharmaceutical compositions according to  claim 9  for topical application onto human skin and/or hair. 
     
     
       13. The polysiloxanes according to  claim 1 , wherein the number of elements of at least one of the groups (A), (B), (C) and (D) is 5 to 60. 
     
     
       14. The polysiloxanes according to  claim 1 , wherein the number of elements of formula (VII) is 5 to 80. 
     
     
       15. The cosmetic or pharmaceutical compositions according to  claim 9  comprising from 0.5 wt. % to 12 wt. % of the polysiloxanes based on the total weight of the composition.